A set of vehicles under multiple-unit (MU) control, such as a consist of rail vehicles, includes a plurality of vehicles for providing power to propel the consist that are controlled from a single location. Typically, the vehicles are spread throughout the consist to provide increased efficiency and greater operational flexibility. In one example configuration, control data generated at a lead control vehicle is sent through a dedicated, narrow-band radio link to the other, remote vehicles, to control operation of the consist from a single location.
However, under some conditions, radio transmissions between the lead vehicle and the remote vehicles are lost or degraded. For example, on some terrain, long consist configurations lose direct line-of-site between remote vehicles, and radio transmission signals do not properly reflect off of the surrounding terrain to reach the remote vehicles, resulting in a loss of data communication. Such periods of lost data communication result in reduced performance capability, increased fuel consumption, and an overall reduction in reliability of operation of the consist.
The local communications between vehicles in the vehicle consist may include various signals containing messages relating to a wide range of information, including operation, safety, status, and confirmations, among a host of others. The potentially large number of local communications transmitted between vehicles can congest the available bandwidth used to transmit the signals. Signals may get lost in the transmission, resulting in non-receipt of the contained message. Additionally, some vehicle systems may be configured upon non-receipt of certain communications to automatically shut down for safety reasons so that any potential problems with the vehicle system may be discovered. A shut-down caused by non-receipt of a local signal could result in a long delay before the vehicle system resumes its route.